Quarterly Estimated Tax Calculator
This calculator projects your total federal tax for the year: self-employment tax, income tax, the QBI deduction, and Schedule 1-A deductions. It works out which IRS safe harbor applies and what each quarterly payment should be.
How this is calculated
The IRS requires quarterly estimated payments once you expect to owe at least $1,000 in tax for the year after withholding. To avoid an underpayment penalty, your withholding and payments must add up to the smaller of two safe harbors: 90% of this year's projected tax, or 100% of last year's tax (110% if your prior-year adjusted gross income was over $150,000).
Your projected tax combines self-employment tax, computed on 92.35% of net profit and split into a 12.4% Social Security portion capped at the annual wage base, an uncapped 2.9% Medicare portion, and an Additional Medicare Tax of 0.9% above $200,000 ($250,000 married filing jointly), with income tax on what remains after the standard deduction, the QBI deduction, and any Schedule 1-A deductions.
The four payments are due on the same dates each year unless the 15th falls on a weekend or holiday, in which case the deadline moves to the next business day. For tax year 2025:
| Payment | Due date |
|---|---|
| Q1 | |
| Q2 | |
| Q3 | |
| Q4 |
Worked example
Suppose you are single, expect $95,000 of net self-employment profit in 2025, have no withholding, and your 2024 tax was $12,000 on an AGI of $70,000. Your projected tax is $21,103.84, but you only have to pay the smaller of the two safe harbors, which here is 100% of last year's tax:
| Step | Amount |
|---|---|
| Self-employment tax (Schedule SE) | $13,423.07 |
| Adjusted gross income (AGI) | $88,288.46 |
| Standard deduction | $15,750 |
| Qualified business income (QBI) deduction | $14,507.69 |
| Schedule 1-A deductions | $0 |
| Taxable income | $58,030.77 |
| Federal income tax | $7,680.77 |
| Additional Medicare Tax | $0 |
| Total projected tax for the year | $21,103.84 |
| 90% of current-year tax | $18,993.46 |
| 100%/110% of prior-year tax | $12,000 |
| Required annual payment (the smaller safe harbor) | $12,000 |
| Expected withholding | $0 |
| Remaining balance to pay in estimated installments | $12,000 |
| Payment due each quarter | $3,000 |
Open this example in the calculator to change any figure.
Sources
Frequently asked questions
- What if I don't have a prior-year return to compare against?
- Uncheck "I have a full 12-month prior-year tax return." The calculator then uses only the 90% current-year safe harbor, matching the Form 1040-ES instructions for taxpayers without a full prior year to compare against.
- Does this calculator handle itemized deductions or capital gains?
- No. It assumes the standard deduction and does not model capital gains, qualified dividends, or credits. If any of these apply to you, treat this as a starting estimate rather than a final figure.
- How is the QBI deduction estimated?
- Below the phase-in threshold, it is 20% of qualified business income. Within the phase-in range, this calculator applies a straight-line reduction as an approximation. The exact figure depends on W-2 wages paid and the unadjusted basis of qualified property, which this calculator does not model.
- What happens if I miss a payment or pay late?
- The IRS charges a penalty on each underpayment for the number of days it remains unpaid, calculated separately for each payment period. Paying the full required amount by the next due date does not erase a penalty already accrued on an earlier missed payment.
- Can I pay all four quarters at once?
- Yes. You can pay the full year's estimated tax with the first payment, or in four equal installments by each due date.
- Do farmers and fishers use different rules?
- Yes. If at least two-thirds of gross income is from farming or fishing, the safe harbor percentage and due dates differ. This calculator does not model those special rules.